6-Some techniques to avoid for a good SEO
The Spamdexing is a technique causing spam in the site by abusing on the SEO
The keyword stuffing is to belabor keywords that you want to highlight within the meta tags and the visible content of the page. Moreover, excessive use of keywords in the metadata could explain why more engines do not take into account the meta description and keyword positioning in a page.
c-black hat SEO
The black hat SEO is a technique used to try to find « loopholes » in the algorithm engine and try to use techniques condemned by them to improve the positions of its web pages in the results